Generic storage phosphor plates and devices are used, in particular for medical purposes, in the field of computer radiography (CR). Here, X-rays are recorded in so-called storage phosphor layers, whereby the X-ray radiation passing through an object, for example a patient, is stored as a latent picture in the storage phosphor layer. In order to read out the stored picture, the storage phosphor layer is irradiated with stimulation light, and so stimulated into emitting emission light, the intensity of which is dependent upon the respectively stored picture information. The emission light is collected by an optical detector and converted into electric signals which can be further processed as required and shown on a monitor or on a corresponding display unit, such as eg. a printer.
In certain applications, the storage phosphor layer is applied to a support layer which is partially transparent for the stimulation light so that the storage phosphor layer can be stimulated by irradiating with stimulation light from the side of the support layer.
The problem can arise here that part of the stimulation light in the region of the upper boundary surface between the support layer and storage phosphor layer is reflected or dispersed back into the support layer by reflection and/or dispersion and reflected back in the direction of the storage phosphor layer on the lower boundary surface of the support layer. In such cases, in particular with support layers with a large thickness, regions of the storage phosphor layer are stimulated which are so far away from the region of the storage phosphor layer currently to be read out that the emission light emitted from them can no longer be collected. The consequence of this so-called advance read-out of individual regions is that with a subsequent, actual read-out of these regions, a reduced intensity of the emission light is obtained, and this leads overall to a detrimental effect upon the picture quality.
It is the objective of the invention to provide a storage phosphor plate and a corresponding device and a radiography module for reading out this type of storage phosphor plate with which an improved picture quality can be achieved.